Study of the functional role of the ascending norepinephrine projections to the forebrain is proposed, by means of correlated neurochemical, morphological and behavioral observations. An elevation of forebrain dopamine concentration, which was previously observed to follow selective electrolytic damage to the ascending norepinephrine axon system, will be analyzed. Morphological and biochemical assay studies are proposed to determine if a neuroplastic response such as collateral sprouting is responsible for the dopamine increase. Emphasis will be placed on discovering the areas of the forebrain in which the increase is occurring, and on exploring the possible correlation of increased forebrain dopamine with the behavioral changes produced by the lesion. Additionally, following either neurochemical (6-hydroxydopamine) or electrolytic lesions of the ascending norepinephrine projections to the forebrain, the ingestive behavior and reactivity to electric foot shock of rats will be observed for lesion induced alterations. The animals will also be observed for recovery of these behaviors due to regeneration, since the neurochemical lesions have been reported to be reversible in certain cases. Furthermore, the morphological effects of these two types of lesions will be compared by means of fluorescence, light and electron microscopic studies.